A billboard shows how the Jiangdu Water Conservancy, a 1960s irrigation scheme, will be remodelled. Photo: Simon Song

You Guoying was welding the bottom of her boat, moored on a river bank in the suburban Jiangdu district of Yangzhou, Jiangsu province. She has been fishing the Mangdao River and nearby waterways for more than four decades.

After taking several months off for the winter, she had been expecting to start this year's fishing season.

But this year brings a new worry: can her nets endure the rush of water?

She dips her boat into the water near where officials installed a sluice gate, which controls water levels. Adjacent to the gate is the starting point of a 1,467km effort to draw water from the Yangtze River to the northern provinces of Shandong and Tianjin. Four huge pumping stations take in water that links to the Yangtze.

"When the pumping stations are put into full operation, the water rushes towards the gate at a very high speed, making it impossible for fishing nets to stay in the water," You said. On those days, she catches no fish.

The pumps were tested last summer for several days. She fears that the abrupt change in water flow will suddenly start again.

About 40 fishing families like You's are caught in the same uncertainty. For decades, they have been living on boats in nearby waterways, catching and selling fish at wet markets in Yangzhou, barely making ends meet. On water-pumping days, they would have no harvest at all.

The South-North Water Diversion Project, which is projected to cost more than 500 billion yuan (HK$620 billion), will transfer water from China's wetter south to arid northern cities by moving it from the Yangtze River to cities in Shandong province, including Dezhou, Jinan and Weihai, where urbanisation has ravaged local resources.

The man-made engineering feat offers another example of China's quest to rein in her rivers.

From the starting point of the project's eastern route in Yangzhou, Jiangsu to Dongping county, Shandong, 13 groups of pumping stations are being built to raise water levels by 65 metres, needing 3.8 to 5.8 billion kilowatt-hours of electricity, according to official estimates.

The pumping station in Suqian, Jiangsu, which officials say is the largest in Asia, can move up to 200 tonnes of water each second.

In this section of the project, the ancient Grand Canal - which connects Hangzhou to Beijing - was linked with nearby waterways and four lakes to serve as the diversion line.

In Dongping, the water streams into a channel that crosses the Yellow River some 70 metres underground and flows to the northern cities in Shandong through ditches and pipelines. A second phase will eventually transport the water to Tianjin.

Government accounts say the easterly route will help relieve a water scarcity crisis in the parched north, eventually benefiting 100 million people.

The easterly route has attracted less public attention than the central route - from Hubei to Beijing - for which at least 400,000 people have been forced to relocate. Also controversial is the westerly route, slated to pass through the Bayan Har Mountains on the Tibetan plateau. It has been delayed indefinitely because of ecological concerns.

Still, the lives of numerous people in the communities along the eastern route have been thrown into a swirl of change and uncertainty as authorities scramble to ensure the expensive project will deliver its on its promises.

One of many challenges will be to guarantee that the water transported is clean and safe. This poses the biggest problem for the eastern route, as the waterways - part of the Grand Canal - were once a major shipping route and have also collected large amounts of waste from factories in highly industrialised Jiangsu province.

The four freshwater lakes along the transfer line were also major fishing sites, providing the main source of income for many local fishermen. But the lake water has become polluted with excessive nutrients from fish farms and other aquaculture.

Aquaculture emissions are not as visible as the industrialised pollution that changes the colour of the water. But the excessive nutrients led to the rampant growth of summer weeds and algae in some of the lakes, according to media reports.

The authorities have invested heavily in cleaning the area. The government has relocated polluting factories, removed silt from the river beds and built sewage treatment plants to process both industrial and urban waste water. Ditches have been dug to catch discharge so it doesn't pollute the water diversion line.

The lakes are crucial stops along the diversion line: they will replenish the transfer route when there is not enough water and catch the overflow when there is flooding. They could also function as ecological buffers to improve quality of the water.

But there is a prerequisite for them to function properly: the lake water has to be clean. As a result, fishing communities along the lakes are being forced to quit their decades-old means of making a living. The compensation they are being offered hardly covers their losses, they say.

The local government has asked families who run big fishing operations to cease what it calls polluting practices so it can clean up the water.

A few years ago, nearly 90 per cent of Baima Lake - covering an area of 113 sq km - was clogged with fishing nets and cages, local media reported. All the fishing nets and cages are gone now, and the Huaian government is considering developing ecotourism in the area.

What else can we fishermen do? I’ve … got no other skills

LONG ZHONG

In 2010, the local government offered Long Zhong, a 42-year-old villager in Hongze county outside Huaian, less than 40,000 yuan for 3.33 hectares of fish farms he kept in the lake.

Long considered himself lucky. He still has a plot of farmland to till. Other fishing families living on boats were asked to relinquish their boats and fishing equipment for monetary compensation and social insurance. "Those who refused to do so would be brought to the police station for one day or two," Long said. Many families journeyed to other provinces looking for fishing opportunities, he said.

"What else can we fishermen do? I've been in this business for more than 20 years and have got no other skills," Long said.

Another villager, Long Jingyou, 67, said that since he quit fishing in 2010 his family income had shrunk by half, to about 50,000 yuan a year.

Fishermen in Yongshengnan village outside Jining city, Shandong, have been faced with a similar situation. Over years of development, the Weishan lake bordering Jiangsu and Shandong provinces has turned into a huge fish farm. Some of the local villagers have made a comfortable living raising fish, crab, lobster and duck and harvesting water chestnuts and other water plants in the man-made ponds.

"The government encouraged villagers to develop aquaculture in the 1980s to boost development, and it has become a major income source for us," said Li Guangyao, a 52-year-old former village official.

But when the water diversion project is fully operational the water level will rise by about one metre, to 33.2 metres, submerging some low-lying man-made ponds in the middle of Weishan lake, Li said.

Villagers thought they were not treated fairly in this process

LI GUANGYAO, FORMER OFFICIAL

As authorities offer compensation for the effects of the rising water levels, some villagers find themselves confused by the requirements to receive it.

"Why was my pond not eligible to get the compensation when another one next to mine received compensation?" asked a villager standing on a dyke and pointing at two ponds. "If that one is going to be affected by the water, how is it possible for mine to stay unaffected?"

The water authorities took aerial photographs last year and decided the compensation based on each pond's altitude, Li said.

"But villagers thought they were not treated fairly in this process, and have yet to receive a satisfactory explanation from the government," he said.

Li said things may get worse for villagers when the diversion project is fully operational. Their incomes could be greatly reduced because they can no longer farm in the water.

The central government has urged the local officials to clean up the lake as soon as possible. But pollutants such as fish feed and excessive nutrients from aquaculture practices have accumulated for nearly two decades.

The pollution curse has also haunted other fishermen along the water diversion route. Villagers in Gupang village, outside Taian city in Shandong province, were convinced that a test of the water diversion project last June was to blame for the deaths of their fish in the Dongping Lake.

A villager who gave only his surname, Zhang, for fear of government retaliation, said all his caged fish died in June last year. Like other residents of the village, he believed that a pumping station used in the water diversion project channelled industrial pollution into the lake, costing him more than 100,000 yuan.

The local government has rejected his claim, saying the fish died because the polluted waters had deprived them of oxygen. Zhang disputed that, saying his oxygen-enriching equipment should have saved the fish.

"Such things never happened before, and no one dares to speak now," he said.

County authorities squelched villagers' attempts to petition to the city government. Instead, officials paid each household 5,000 yuan compensation, regardless of what they had lost. Several petitioners were briefly detained and their phones are still bugged, villagers said.

Zhang shared the uncertainty of many in his village as well as that of You, the woman who has been fishing in the Mangdao for decades, when he said: "Who knows if such thing will happen again? We'll still have to go fishing, there is no other choice."

This article appeared in the South China Morning Post print edition as Flooded with progress